Gas monitoring device



FIG. 1 is a front perspective view of the gas monitoring device.

FIG. 2 is a front view thereof.

FIG. 3 is a back perspective view thereof.

FIG. 4 is a left side view thereof.

FIG. 5 is a right side view thereof; and,

FIG. 6 is a top view thereof.

The broken lines shown in the Figures show portions of the gas monitoring device that form no part of the claimed design. 

CLAIM The ornamental design for a gas monitoring device, as shown. 